javascript map
array.map((item) => {
return item * 2
} // an example that will map through a a list of items and return a new array with the item multiplied by 2const myArray = ['Sam', 'Alice', 'Nick', 'Matt'];
// Appends text to each element of the array
const newArray = myArray.map(name => {
return 'My name is ' + name;
});
console.log(newArray); // ['My name is Sam', 'My Name is Alice', ...]
// Appends the index of each element with it's value
const anotherArray = myArray.map((value, index) => index + ": " + value);
console.log(anotherArray); // ['0: Sam', '1: Alice', '2: Nick', ...]
// Starting array is unchanged
console.log(myArray); // ['Sam', 'Alice', 'Nick', 'Matt']// The map() method creates a new array populated with the
// results of calling a provided function on every element
// in the calling array.
const array1 = [1, 4, 9, 16];
// pass a function to map
const map1 = array1.map(x => x * 2);
console.log(map1);
// expected output: Array [2, 8, 18, 32]const numbers = [0,1,2,3];
console.log(numbers.map((number) => {
return number;
}));function listFruits() {
let fruits = ["apple", "cherry", "pear"]
fruits.map((fruit, index) => {
console.log(index, fruit)
})
}
listFruits()
// https://jsfiddle.net/tmoreland/16qfpkgb/3/array.map( item => item.id )
array2.map( item => item.toString() )
array2.map( item => item * 3 )
// this will apply a transformation to all elements of an array
// "" item => something "" is the transformation (function)The map() method creates a new array with the results of calling a provided function on every element in the calling array.// make new array from edited items of another array
var newArray = unchangedArray.map(function(item, index){
return item; // do something to returned item
});
// same in ES6 style (IE not supported)
var newArray = unchangedArray.map((item, index) => item);